Breathable and waterproof lining structure for footwear and garment

ABSTRACT

A waterproof and breathable lining structure includes a sheet-like waterproof and breathable foaming cushion layer made of a composition of a predetermined amount of low density polyethylene (LDPE) and a predetermined amount of foaming agent such as azodicarbonamide (ADCA), and a fabric lining layer integrally adhered to one side of the cushion layer to form the lining structure. The cushion layer is made by a process including the steps of: (a) palletizing raw materials including the low density polyethylene and the foaming agent such as Azodicarbonamide (ADCA); (b) extruding the palletized raw material to make a solid sheet; (c) cross-linking the solid sheet by an E-beam to form an irradiated matrix; (d) foaming the irradiated matrix into the sheet-like foaming cushion layer.

CROSS REFERENCE OF RELATED APPLICATION

This is a divisional application of a non-provisional application,application Ser. No. 10/825,728, filed Apr. 16, 2004 now U.S. Pat. No.7,316,985.

BACKGROUND OF THE PRESENT INVENTION

1. Field of Invention

The present invention relates to a kind of lining structure, moreparticularly, relates to a lining structure employing a kind of anirradiation cross-linked, foam sheet product, which is water repellentand air breathable to be used in shoe making and garment industry.

2. Description of Related Arts

Commonly, people desire to seek a pair of dry and comfort shoes. This isdue to the fact that dry feet make a huge difference when walking in therain or in a wet working environment. Likewise, waterproof garments arealso under heavy requirements in different applications especially inrainy regions. People wish to keep drier by remaining waterproof afterexposures to a wet circumstance, particularly those people whofrequently encounter to contaminants such as perspiration, oils, fuels,rains, detergents, and so on.

Thanks to the development of the modern chemistry industry, waterproofproducts are available, such as the traditional water repellent fabricbases on polyurethane chemistry which may degrade with exposure to cold,flexing, and chemicals. Instead, the GORETEX™ and SYMPATEX™ materialsutilize a fundamentally different bi-component membrane technology thantraditional fabrics by combining the breathability with the durablewaterproofness.

Undertaken an exercise of intensity while wearing waterproof orwater-resistant clothes, people would feel uneasiness. Under that kindof condition, body moisture evaporated from the skin for the purpose ofcooling is unable to escape due to the overlying barrier that is thefabric of the garment.

As a result, these current waterproof materials, such as GORETEX™ orSYMPATEX™, could allow perspiration vapor to escape from the garment andshoe, so the wearer feel more comfortable. In other words, GORETEX™ andSYMPATEX™ fabric allows more sweat vapor to be released than otherwaterproof fabric alternatives so wearer could stay drier and cooler inwarmer, wetter conditions. It is worth to mention that this sweat vaportransferring also helps prevent conductive heat loss in cold weather bykeeping wearer's body and clothing layers drier.

In short, the current materials have the property that water vapor inthe air may pass through its pores, but liquid water may not, commonlysaid to be ‘breathable’. So through the wonders of physics andchemistry, the same impenetrable water barrier actually transportperspiration, so user's body could breath.

Currently, the production of these current waterproof fabrics is mainlybased on the laminating processes. Among those products, GORETEX™ fromW. L. Gore, an American company, and SYMPATEX™ from Europe areundoubtedly dominating ones on the market. Both GORETEX™ and SYMPATEX™employed the laminating process which involves a process in which alayer of lining film is adhered onto a layer of fabric.

However, this kind of current waterproof material also suffers somedrawbacks. First of all, the production process is too expensive to beafforded by common consumers. This is due to the fact that theapplication of these laminating equipments cannot be applied usingexisting textile production processes. Second, synthesis of the liningfilm is costly and garments with this waterproof modification aresignificantly expensive like luxury goods. Meanwhile, although SYMPATEX™is 100% waterproof, it is essential that the outer fabric also has awater repellent finish. Otherwise, the outer fabric would soak up thewater and the garment would become unnecessary heavy.

As a result, it is highly desirable to develop an inexpensive liningstructure, which is capable of being used in shoe making and garmentindustry as a substitute alternative material, wherein said liningstructure is water proof and air breathable, and preferably, made ofcheaper traditional waterproof materials.

SUMMARY OF THE PRESENT INVENTION

A main object of the present invention is to provide a kind ofinexpensive lining structure, which is water proof and air breathable,being used for waterproof shoes and garments.

Another object of the present invention is to provide a kind ofinexpensive lining structure, which is water proof and air breathable,as a substitute alternative material that doesn't need expensiveproducing equipments and costly raw materials.

Another object of the present invention is to provide a kind ofinexpensive waterproof and air breathable lining structure, which offerssatisfied strength and durability to be used as lining layer in footwearand garments.

Accordingly, in order to accomplish above objects, the present inventionprovides a waterproof and breathable lining structure comprising;

a sheet-like waterproof and breathable foaming cushion layer made of acomposition of a predetermined amount of low density polyethylene (LDPE)and a predetermined amount of foaming agent such as azodicarbonamide(ADCA); and

a fabric lining layer integrally adhered to one side of the cushionlayer to form the lining structure.

In an embodiment of the present invention, the waterproof and breathablelining structure further comprises a sheet of cover layer made of fabricmaterial integrally adhered to another side of the cushion layer to actas an interior surface of the lining structure to contact with a wearerwhile the lining layer acting as an exterior surface to enable bettergluing ability with the outside layer of a footwear or a garmentproduct.

The waterproof and breathable foaming cushion layer is made by a processcomprising the steps of:

(a) Palletizing raw materials including the low density polyethylene andthe foaming agent such as Azodicarbonamide (ADCA);

(b) Extruding the palletized raw material to make a solid sheet;

(c) Cross-linking the solid sheet by an E-beam to form an irradiatedmatrix;

(d) Foaming the irradiated matrix; and

(e) Cutting and seaming the irradiated matrix into the predeterminedshape.

These and other objectives, features, and advantages of the presentinvention will become apparent from the following detailed description,the accompanying drawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a breathable & waterproof liningstructure which is made into an interior lining structure of a shoeaccording to a preferred embodiment of the present invention.

FIG. 2 is a block diagram illustrating the process for producing thelining structure according to the preferred embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention provides a waterproof and breathable liningstructure which is embodied to produce a shoe lining structure forfootwear such as boot as shown in FIG. 1. Of course, it can also be madeas the lining structure of garment product such as a jacket.

The waterproof and breathable lining structure 10 of the presentinvention comprises a sheet-like waterproof and breathable foamingcushion layer 11 and a fabric lining layer 12 integrally adhered to oneside of the cushion layer to form the lining structure.

According to the preferred embodiment of the present invention, thewaterproof and breathable lining structure 10 further comprises a sheetof cover layer 13 made of fabric material integrally adhered to anotherside of the cushion layer 11 to act as an interior surface of the liningstructure 10 to contact with a wearer while the lining layer 12 actingas an exterior surface to enable better gluing ability with the outsidelayer of a footwear or a garment product.

The lining structure 10 to be used in footwear and garments is producedby using polyolefin materials and additives such as foaming agents.According to the preferred embodiment of the present invention, thesheet-like waterproof and breathable foaming cushion layer 11 is made ofa composition of a predetermined amount of low density polyethylene(LDPE) and a predetermined amount of foaming agent such asazodicarbonamide (ADCA).

A producing method for preparing the lining structure 10 which is waterrepellent and air breathable comprises the steps of:

(a) palletizing raw materials;

(b) extruding the palletized raw materials to make a solid sheet;

(c) cross-linking the solid sheet by an electron-beam to form anirradiated matrix;

(d) foaming the irradiated matrix into the sheet-like foaming cushionlayer; and

(e) cutting and seaming the foaming cushion layer into predeterminedshape.

Furthermore, to improve the properties of the polyolefin materials, itsproduction adopts irradiation technology as a key process, andpolyolefin molecules are crosslinked by electron-beam irradiation inthis process. Finally, the materials are foamed at general atmosphereand high temperature to provide a foamed material possessing waterrepellent and air breathable property.

Accordingly, the polyethylene is cross-linked by irradiation. And thefoam material is formed by the employment of chemical foaming agents.Typically, a cross-linked, polyethylene foam sheet material is providedby mixing a predetermined amount of foaming agent into the polyethylenematerial in an extruder, and then the cross-linking process issubsequently followed to form a matrix sheet. Finally, the matrixmaterial is conveyed through an oven and expanded into a generally flat,cross-linked, sheet material.

As a result, the step (a) further comprises the steps of:

(a-1) mixing Polyolefin pellet with foam agent as well as otheradditives in a mixer to form a mixture;

(a-2) extrudingly palletizing the mixture assuring master batch of eachraw material in pellet.

Preferably, the polyolefin material is the LDPE (low densitypolyethylene) or PP (polypeplene). Polyethylene (PE) possesses a numberof beneficial physical and chemical properties when used to produce afoamed sheet, which is crucial in this present invention, since PE/PP iswater repellent whereas air channel are existed for air permeability.

In addition, PE foam material has fine cell air bubble and smoothsurface. Meanwhile, the forming process of the LDPE is flexible with afoaming range from 3 times to 40 times. As a result, the user couldadjust the foaming process according to different applications in shoemaking process.

According to the preferred embodiment of the present invention, thefoaming agent is Azodicarbonamide (ADCA), the additives includeZnO(Zinc-Oxide), ZnSt(Zinc Stearate), and pigment. And the reactionprocess comprises above mentioned raw material with a formulation ratio100 phr LDPE, 18 phr ADCA, 0.1 phr ZnO, 0.1 phr ZnSt, and 1.0 phrpigment.

In the step (b), all master batches of every material according to theformulation ratio is put into an extruder to be extruded into a mothersheet.

In the step (c), according to the preferred embodiment of the presentinvention, the mother sheet is cross linked by an electron-beam(irradiation). The producing method of the present invention adoptsirradiation technology as a key process, and the raw materials'molecules are crosslinked by electron-beam irradiation in this process.Here, crosslinked polymers are usually molded and shaped before they arecrosslinked. As a result, the lining structure in the present inventionprepared by this cross linking process has superb strength as well asprolonged durability.

As mentioned before, although SYMPATEX™ is 100% waterproof, it isessential that the outer fabric also has a water repellent finish.Otherwise, the outer fabric would soak up the water and the garmentwould become unnecessary heavy. So, the GORETEX™ or SYMPATEX™ membraneis rather thin for reserving more space to outer shell materials.Inevitably, the durability and strength is not satisfied. Accordingly,the outer shell of shoe or garment has to be specially prepared forensuring material durability. While the lining structure according tothe first preferred embodiment of the present invention is a foamedsheet of prolonged durability, the thickness of outer shell of shoe orgarments could be substantially reduced and materials source of outershell could be broadened.

Furthermore, irradiation cross-linking technology also facilitatespolymer surface. Meanwhile, it also provides a method that makes an opencell cellular body of polyethylene resin material in crosslinkedstructure, which has a maximum degree of cell interconnection, which isgood in recyclability and excellent in heat resistance or resistance toheat distortion. What is more, the open cell cellular body ofpolyethylene resin and the well interconnection of cell make it possiblefor air permeable. So the IEPE foam in the present invention hasdesirable properties which are comparable with that of GORETEX™ andSYMPATEX™.

Also, the step (d) of the producing process further comprises the stepsof:

(1) rolling said irradiated matrix; and

(2) putting said irradiated matrix into a foaming oven heated by hotair.

As a result, the materials are foamed at general atmosphere and hightemperature. It is worth to mention that during the foaming process inthe step (d), the open cell cellular body is further foamingly expandedthereby the air permeability is assured.

Conclusively, the producing method of the present invention involvesmaking a polyethylene resin open cell cellular body by partiallydecomposing a foaming (expanding) and a crosslinking agent in a foamableand crosslinkable composition of polyethylene resin material in a closedmold, then decomposing the remaining parts of the foaming andcrosslinking agents under an atmospheric pressure to obtain a body withclosed cells from the composition, and finally compressing the thusobtained body to cause the closed cells to be destructed therebyproviding air permeability. As a result, the final foam sheet could beused as lining materials which is waterproof, thanks to PE'swater-repellent property, and air breathable.

Before the step (e), the producing process may further comprises thesteps of attaching the fabric lining layer 12 to one side of the cushionlayer 11 and attaching the sheet of cover layer 13 to another side ofthe cushion layer 11 to form integral layers of the lining structure 10.

In the step (e), the foamed sheet could be cut into predetermined shapeto be used as lining layer in footwear or garments. As known in the art,different foamed sheet could be seamed together by thermoplasticallysealed the stitching edge of said foamed sheet.

The lining structure 10 prepared by the producing method of the presentinvention has a better compatibility with outer fabric. Here, the outerfabric lining layer 12 may be of any suitable garment fabric, rangingfrom fully waterproof, coated or laminated fabric. Fabrics which couldbe utilized for the lining layer 12 range from single or multilayerfully waterproof fabrics which may be laminated with a waterproof layer,or coated or uncoated fabrics, with or without a water repellenttreatment. This is due to the fact that the foaming cushion layer 11 inthe present invention has a flexible thickness thereby proving anadjustable waterproof and air breathable function.

In short, the foaming cushion layer 11 of the present invention can be asubstantially continuous sheet, lining most of the shoes and thegarment. Since the foamed material is so elastic, any cut opening couldbe provided on the sheet for easy deformation to be accommodated insidea shoe mode. More importantly, the foaming cushion layer 11 could be cutinto various shapes to maximize air exchange and to give betterflexibility and movement to the shoes and garments.

To sum up, according to the present invention, it is possible to easilyproduce a polyethylene extruded foam having an elongation, tensilestrength and durability improved over those of the conventional waterproof extruded foams, and particularly, it is possible to easily producea long and thin sheet-like polyethylene extruded foam which is waterrepellent and air breathable as a substitute alternative material beingused in shoe-making and garment industry.

The following table illustrates the result of the present invention in aMaeser Flex-ASTM D2099-00 test for two pieces of sample of liningstructure of the present invention:

Sample ID: Aquashield Membrane Test Specimen ID #1 #2 Suggested Minimum*Initial weight .946 .950 N/A (grams) Final weight .950 .951 N/A (grams)% Percent of .42 .11 11 5-11% max. water Absorbed No. of flexes 28,00028,000 20,000-25,000 Water penetration No No No Yes or No *For US Shoemanufacturers

In view of the above table, the wateproofness of the lining structure 10according to the present invention is illustrated. It is seen that nowater penetration has been tested on the product.

The following table illustrates the result of the present invention in aMoisture Vapor Transmission-ASTM E96-95 test for two pieces of sample oflining structure of the present invention:

Aquashield Membrane Suggested minimum* Sample ID: g/m²/hr mg/cm²/hrmg/cm²/hr #1 70 7.0 20 #2 95.5 9.55 Average 82.75 8.28 *Suggestedminimum for uppers or combination of materials

In view of the above table, the air breathability of the liningstructure 10 according to the present invention is illustrated. It isseen that air permeability is desirable.

One skilled in the art will understand that the embodiment of thepresent invention as shown in the drawings and described above isexemplary only and not intended to be limiting.

It will thus be seen that the objects of the present invention have beenfully and effectively accomplished. It embodiments have been shown anddescribed for the purposes of illustrating the functional and structuralprinciples of the present invention and is subject to change withoutdeparture form such principles. Therefore, this invention includes allmodifications encompassed within the spirit and scope of the followingclaims.

1. A process of producing a waterproof and breathable shoe liningstructure for a boot having an outer shell, comprising the steps of: (a)forming a pair of interior linings each of which is cut into a bootshape, wherein each of said interior linings is made by the steps of:(a.1) forming a sheet-like waterproof and air breathable foaming cushionlayer; (a.2) integrally attaching a lining layer to one side of saidfoaming cushion layer; and (a.3) integrally attaching a cover layer toanother side of said foaming cushion layer; (b) stitching said interiorlinings edge to edge together to form stitching edges; and (c)thermoplastically seaming said stitching edges of said interior liningsto form said shoe lining structure for fitting into said outer shell ofsaid boot; wherein, in the step (a.1), said waterproof and airbreathable foaming cushion layer is made by the steps of: (i) forming apelletized raw material with a low density polyethylene, a foaming agentincluding azodicarbonamide, a pigment, and additives including ZincOxide and Zinc Stearate by the steps of: (i-1) mixing said polyethylenewith said foaming agent, said pigment, and said additives in a mixer toform a mixture; and (i-2) extrudingly pelletizing said mixture intomaster batches comprising said low density polyethylene, said foamingagent, said pigment and said additives in pellet; (ii) extruding saidpelletized raw material to make a solid sheet, wherein all said masterbatches are put into an extruder to be extruded into a mother sheet;(iii) cross-linking said solid sheet by an electron-beam to form anirradiated matrix; and (iv) foaming said irradiated matrix into asheet-like foaming cushion layer by the step of rolling said irradiatedmatrix, and the step of putting said irradiated matrix into a foamingoven heated by hot air.
 2. The process, as recited in claim 1, whereinsaid mixture comprises 100 phr of said polyethylene, 18 phr of saidADCA, 0.1 phr of said ZnO, 0.1 phr of said ZnSt, and 1.0 phr of saidpigment are put into an extruder to be extruded into a mother sheet.